There are well known brake heads assemblies for railway cars by which a brake shoe is pressed against a wheel in order to decrease or stop the rotational speed of the wheel and of the railway car for braking. The brake heads are typically actuated by a pneumatic actuation system.
Generally, a structure called a “brake beam” is mounted transversely in the bogie of a railway car and is linked to a lever, which applies a force in order to press a brake shoe of a brake head against a wheel to apply a braking force to the wheel. Often, the brake beam has two ends and each end is attached to a respective break head. Examples of brake beam assemblies may be appreciated from U.S. Pat. Nos. 2,170,121, 2,193,580, 2,427,548, 2,499,905, 2,702,614, 2,722,291, 2,753,960, 3,998,299, 4,830,148, 6,138,800, 6,155,387, 6,234,283, and 6,332,515, and U.S. Publication No. 2006/0219502.
There are many brake beams in the market which claim to be resistant to mechanical stress without adding weight to the brake beam, such as that disclosed in the U.S. Pat. Nos. 5,810,124, 6,155,388, and 6,155,389. For example, U.S. Pat. Nos. 5,810,124, 6,155,388, and 6,155,389 each disclose a brake beam assembly made up of a compression member, a tension member, a strut connected to the tension member and to the compression member, and two brake heads with recesses. The ends of the compression member and of the tension member are disposed within the recesses of the brake heads together with at least two fasteners per recess. Each of the fasteners are substantially perpendicular to the tension member and to the compression member. No other structural elements are present in the recesses of the brake heads.
Although it is mentioned that the above referenced brake beam designs provide adequate high static strength and fatigue resistance, the end extension and brake head are formed as a single piece, which may be problematic when the brake head has to be replaced. For instance, such a brake head design requires the tension member and compression member portions of the brake beam to be cut, or otherwise disassembled, in order to remove a damaged brake head from the brake beam. Furthermore, since all of the pressure from the breaking action and the forces derived from maintaining the brake beam in place are concentrated in the brake head component, which has an integral extension component, the brake heads are prone to experience significant fatigue, which may damage the brake head or other components of the brake beam assembly. Such fatigue may also cause the brake head to fail.
A new brake beam assembly is needed that provides a design permitting the brake heads to be easily replaced without requiring other components of the brake beam assembly to be cut, removed, or disassembled from a railway car to which it is mounted. Preferably, such a brake beam assembly would provide a design that increases the service life of brake head components and would provide improved high static strength and fatigue resistance. Such a design would also preferably have a relatively low weight and a relatively low cost for manufacture.
A typical brake beam suffers the wear of the brake heads as the must common condition for brake beam replacement. Under the present design, the concept of a replaceable brake head is followed, by having the end extension as a separate element from the brake head, where the brake head can be removed from the beam with a minimum effort while the beam is still mounted on the freight car truck. A new brake head can be applied to the same brake beam end by simple and normally available tools to the maintenance railroad crews, thus reducing significantly the maintenance cost and time to the car owner and the railroad, by being able to reutilize the non-damaged majority of the brake beam without disassembling the freight car, and without the present need to remove the freight car from the train to later be displaced toward a specialized car shop for its brake beam replacement.
The present invention is directed toward overcoming one or more of the above-mentioned problems.